Studies on the stimulation of cAMP metabolism in human lymphocytes by latex polymers

Enhancement of adenosine 3',5'-monophosphate in human mononuclear and polymorphonuclear leukocytes by snake venoms

Snake venoms contain compound(s) that enhanced cyclic AMP content in human mononuclear leukocytes maximally after 5 min of incubation at 37 degrees C. The effect was time- and dose-dependent. The half-maximal stimulation of cyclic AMP production by black cobra venom was found at 0.45 micrograms of venom/ml and the value of the Hill coefficient was 0.7. The black cobra venom enhanced the cyclic AMP content in the cells at 4, 22, and 37 degrees C. Similar increase in the cyclic AMP content by six snake venoms was found in human polymorphonuclear leukocytes. The most active venom was from puff adder (Bitis arietans). The data suggest that one of the effects of the snake venoms may be rapid enhancement of cyclic AMP level in the affected cells.

Increased ATP-ase activity of lymphocytes after rosette formation with sheep red blood cells

In a number of experiments it was demonstrated that in the E-rosette assay for human T-lymphocytes using sheep red blood cells, the ATP-ase activity of the lymphocytes increased in proportion to the number of rosettes being formed. Also, after increasing the number of rosettes by treatment of the sheep red blood cells (SRBC) with neuraminidase and after diminishing the number of rosettes by treatment of the lymphocytes with antilymphocyte globulin (ALG), change in the ATP-ase activity was proportional to alterations in the number of rosettes being formed. ALG itself stimulated the lymphocyte ATP-ase activity, possibly through activation of the same receptor sites as used by SRBC.